JPH03135566A - Photopolymerizable mixture and recording material manufactured from said mixture - Google Patents

Abstract

PURPOSE: To enable development with an aqueous solution by using a combination of a polymer binder having repeating vinylacetal units, a free-radically polymerizable compound having an ethylenically unsaturated terminal group and a boiling point of >100 deg.C in normal pressure, and a photopolymerization initiator capable of initiating polymerization of this compound under irradiation with chemical rays. CONSTITUTION: The photopolymerizable mixture comprises the polymer binder having repeating vinylacetal units, and the free-radically polymerizable compound having an ethylenically unsaturated terminal group and a boiling point of >100 deg.C in normal pressure, and the photopolymerization initiator capable of initiating polymerization of this compound under irradiation with chemical rays or a combination of them, and the binder is a graft polymer and its main chain is a polyurethane and chains comprising vinyl alcohol units and vinylacetal units are grafted from the main polyurethane chain, thus permitting the obtained photopolymerizable mixture to be adapted to the manufacture of the printing plate, especially, a lithographic printing plate, and that of photoresists, and to be developed with an aqueous solution containing no solvent.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention comprises a polymeric binder, a polymerizable compound having at least one ethylenically unsaturated double bond in the molecule, and a photoinitiator or a photoinitiator, which can be developed in an aqueous solution. It relates to photopolymerizable mixtures containing an initiator system and suitable for the production of photosensitive recording materials, in particular lithographic printing plates and photoresists.

(Prior art) A photopolymerizable mixture containing a water-soluble binder is DE-B15.
22362 and DE-A1917917. In general, these mixtures can be easily and without forming a thin skin (viLhou
t 5cun+a-1ng) can be developed, but,
These give rise to the disadvantage that in lithographic printing, cured image areas containing water-soluble binders are more easily wetted by the dampening solution and are attacked by the dampening solution during production in advanced printing operations.

Mixtures of the type mentioned above are also described in DE-A 2053363. Binders included therein include reaction products obtained from polymers containing hydroxyl or amino groups and at least one saturated alkylsulfonyl isocyanate, alkoxysulfonyl isocyanate, arylsulfonyl isocyanate or allyloxysulfonyl isocyanate.

In combination with diazonium salt condensation products or photopolymerizable mixtures, a binder is included to provide a photosensitive layer. However, the resulting mixture can only be developed with aqueous alkaline solutions if the binder used has a high rancidity, which has an adverse effect on the abrasion resistance and printability of the cured layer.

EP-A 167963 describes a negative-working photosensitive material suitable for the production of lithographic printing plates, containing a diazonium salt polycondensate, an ethylenically unsaturated compound which can be polymerized by free-radical methods, a photoinitiator and a water-soluble polymer binder. A mixture of sexes is disclosed. High printing performance can be achieved when polyvinyl acetal is used as the binder.

However, in this case development is only carried out together with a solution containing a large amount of organic solvent.

DE-A 3722089 describes graft polymers comprising a grafted bone core and polyurethane as grafted vinyl ester units which are at least partially saponified to give vinyl alcohol at position 111. These polymers are suitable as binders for pigments, for the preparation of printing inks, for thermoplastic adhesives and solvent tooth adhesives, as constituents of varnishes or as coatings for fibers, films and metals, for thermoplastic moldings. It is.

JP-A 246,047/87 describes a photopolymerizable mixture containing a graft polymer of polyurethane having mercapto groups and polyvinyl alcohol.

The above DE-A3722 acetalized with aldehyde
The graft polymer obtained from the graft polymer described in 089 is disclosed in the prior art German patent application P38358
40.9.

In the prior art German patent application P3824146゜3,
Photocurable elastic mixtures are described which contain compounds polymerized by free-radical methods, photoinitiators and graft polymers according to DE-A 3732089 which can be dissolved or dispersed in aqueous solutions as binders.

Object of the invention Suitable for use in the production of printing plates, in particular for the production of lithographic printing plates or photoresists, which possesses all the advantages of known photopolymerizable compositions and which can be developed by extremely solvent-free aqueous solutions. , therefore tap water
) produces a printing plate with high light speed and high image resolution at the same time without exceeding the precipitates that would interfere when a developer solution containing
It is an object of the present invention to provide photopolymerizable mixtures which have a long shell life and which offer properties that are to date only possible in printing plates that require the addition of relatively large amounts of organic solution in the development process.

(Disclosure of the Invention) According to the present invention, as essential components: (a) a polymer binder having repeating vinyl acetal units; (b) a polymer binder having at least one terminal ethylenically unsaturated group and a boiling point exceeding 100°C under normal pressure; and (c) a compound or combination of compounds capable of initiating the polymerization of the compound (b) under the action of actinic light.

The mixtures of the invention are characterized in that the binder is a polymer, in which the grafting backbone is a polyurethane onto which chains containing vinyl alcohol units and vinyl acetal units are grafted.

According to the invention there is also proposed a photopolymerizable recording material comprising a layer support and a photopolymerizable layer in which said photosensitive layer comprises a mixture as defined above.

The graft polymers contained in the mixtures of the invention are described in the prior art German patent application P3835840.9. To make it, a carboxylic acid vinyl ester and any other ethylenically unsaturated compound that can be copolymerized with it are grafted onto a polyurethane graft backbone (main chain) and fully or partially saponified. . The polymer having vinyl alcohol units thus obtained is further reacted with an aldehyde to produce polyvinyl acetal.

The proportion of the components to be grafted is generally between 10 and 95, preferably between 30 and 90, in particular between 4 and 4, based on the total grafted polymer.
It is 0 to 80 weight Q%.

The graft skeleton consists of polyurethane having at least two urethane groups in the molecule, and the number of urethane groups per molecule generally has a value exceeding 2, although no particular upper limit is given.

The polyurethane employed as the graft skeleton is produced from diols and diisocyanates by the usual methods for polyurethane synthesis. In principle, all diols commonly used for polyurethane synthesis can be employed. Cycloaliphatic diols, such as cyclohexanediol, especially 2-12
Preference is given to aliphatic diols having carbon atoms of . Preference is also given to polyether diols, such as polypropylene oxide, polybutylene oxide and copolymers of ethylene oxide, propylene oxide and butylene oxide, especially block copolymers thereof, having a molecular weight of from 200 to 10.000, more preferably from 400 to 1.500. Particularly preferred are polyethylene oxides with Polyether diols are low molecular weight aliphatic diols, such as 1,4-butane-diol,
], 3-propanediol, ethylene glycol, diethylene glycol, 1,2-hexanediol, 1.2
- Advantageously employed in combination with propanediol, bentanediol or cyclohexanediol. The molar ratio of polyether diol to low molecular weight aliphatic is preferably from :0.1 to 1:0.7.

Diisocyanate components that may be employed are aromatic diisocyanates. Aliphatic and cycloaliphatic diisocyanates are preferred. Preferred aliphatic diisocyanates are those having 2 to 12 carbon atoms in the aliphatic radical;
For example, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate and 2,
2.4-trimethylhexamethylene diisocyanate. Preferred cycloaliphatic diisonanates include, for example, 1
, 4-diisocyanate-cyclohexane, cyclohexylmethanol-4,4'-diisocyanate and isophorone diisocyanate. Particular preference is given to hexamethylene diisocyanate and isophorone diisocyanate.

The molar ratio of diisocyanate component to diol component is preferably from 1:0.99 to 1:0.5, especially from 1:0.98 to 1:0.7.

The average molecular weight of the polyurethane is 200 to 100.000, particularly 1,000 to 50.000, particularly preferably 3,000 to 25.00.
It is 0.

Carboxylic acid vinyl esters having 3 to 20, preferably 4 to 14 carbon atoms are used for grafting onto the polyurethane. Preference is given to vinyl acetate and/or vinyl propionate, especially vinyl acetate.

Mixtures of vinyl acetate and/or vinyl propionate with vinyl versatate are also preferred.

Particularly in the case of graft polymerization following partial or complete hydrogenation of the product, the co-use of vinyl propionate in addition to vinyl acetate is advantageous during the grafting. Additionally, a copolymerizable mixture of carboxylic acid vinyl esters, preferably a mixture of vinyl acetate and a small amount of vinyl versatate, is grafted.

Grafting with various carboxylic acid vinyl esters in the form of block copolymers, optionally in further combination with ethylenically unsaturated and copolymerizable monomers, may also be advantageous. Furthermore, the carboxylic acid vinyl esters are grafted together with other ethylenically unsaturated (polymerizable monomers), especially acids such as maleic acid, itaconic acid, mesaconic acid, crotonic acid, acrylic acid or their esters.

The resulting graft polymer can be converted to a partially or fully saponified product by hydrolysis, alcohol rinsing or transesterification;
at least 30, preferably 45 to 9, relative to the number of moles in the 1st position
It is 9 mol%.

L polyurethane graft skeleton! The preparation of heptagraft polymers is described in DE-A 3732089.

The saponified graft polymer is acetalized in an acidic medium in a known manner.

Substituted aliphatic aldehydes with 1 to 20 carbon atoms and substituted aromatic aldehydes are used for the acetalization. Preference is given to aliphatic aldehydes with 1 to 5 carbon atoms, such as n-butyraldehyde, isobutyraldehyde, propionaldehyde or forno-aldehyde.

Also suitable are substituted or unsubstituted penzaldehydes, such as penzaldehyde, p-chloropenzaldehyde or p-methoxybenzaldehyde. It is also possible to use some of these aldehydes in combination.

The degree of acetalization of the grafted polyvinyl acetal used as a binder according to the invention is such that the eEQ of the non-acetalized polyvinyl alcohol units in the grafted polyvinyl acetal is between 18 and 60, particularly preferably 20.
~ 45 mol 96, at each point with respect to the mol of vinyl alcohol units contained in the saponified graft polymer used, it can be up to 55 mol %, as given in terms of the original amount as vinyl ester units. The hydroxyl number of the preferably chosen ready-to-use binder is between 100 and 600, preferably 2.
Should be between 00 and 500.

Acetalization is carried out using two separate methods.

According to a first method, the graft polymer is dissolved and dispersed in an alcohol or a water/alcohol mixture mixed with an aldehyde or a mixture of aldehydes and a dissolving amount of an organic or inorganic acid and heated. The resulting polymer solution, which is suitable and also contains an antioxidant, can be used directly to make mixtures according to the present invention, or the solution can be added dropwise to a non-solvent for precipitation and purification. .

According to the second method, the graft polymer is dissolved in water and mixed with the aldehyde or aldehyde mixture. An aqueous solution of an inorganic or strong organic acid is then added, if appropriate.
Add surfactant and antioxidant and drip at low temperature. As a result, the acetal graft polymer often precipitates. The reaction is completed at an elevated temperature of about 20-60°C. The isolated polymer is purified by washing with water or reprecipitated.

To make grafted polyvinyl acetals in aqueous solvents, 1 to 50, preferably 5 to
A 20% strength aqueous solution of grafted polyvinyl alcohol is prepared. At elevated temperatures, an acid catalyst is preferably used and the solution is then cooled to a temperature below 25°C and the final acetalization reaction is carried out by measuring in an aldehyde preferably within a time period of 3 to 300 minutes. will be held. As is known, aldehyde conversion is often not completed and therefore an excess of aldehyde, preferably 10-20 mol %, is usually added.

In a preferred method, the aqueous solution is allowed to stand at a temperature of 0-5° C. for at least about 30 minutes prior to initiation of the reaction, and the grafted polyvinyl acetal formed is then typically separated as a powdered material after a short period of time. be.

To complete the reaction, the reaction mixture is slowly heated to room temperature, preferably it is heated to an elevated temperature, e.g.
After-react for about 1 to 3 hours.

The amount of acid catalyst added depends in particular on the degree of acetalization to be achieved and is preferably less than or equal to 1.1 mol, with respect to the molar content of vinyl alcohol units.

The resulting grafted polyvinyl acetal is q
1, washed with weakly alkaline water (pH 9-12), and dried. Acetalization products that do not precipitate from the aqueous reaction solution are purified by addition of a precipitating agent and dried.

Acetalization can also be carried out in organic solvents.

Examples of suitable solvents are water-miscible solvents, especially water-soluble alcohols, such as ethanol and/or methanol, into which water is added.

Preferred acid catalysts are organic sulfonic acids, such as toluenesulfonic acid, and mineral acids, sulfuric acid, phosphoric acid, hydrochloric acid or nitric acid. Among these, phosphoric acid and hydrochloric acid are particularly preferred.

For preparation in organic acids, the acid catalyst, aldehyde, and grafted polyvinyl alcohol are dispersed or dissolved in a solvent and the mixture is refluxed.

It is also expedient to add aldehydes during the course of the reaction.

Grafted polyvinyl alcohols that are soluble in organic solvents gradually dissolve as a result of the acetalization that takes place.

When the acetalization reaction is complete, the reaction product is precipitated by adding a non-polar solvent, e.g. an aliphatic hydrocarbon, or by pouring the reaction solution into ice-cold water or into an ice-cold water/alcohol mixture. It is isolated by suction, washed with weakly alkaline water (pH 9-12) and dried.

The preparation of grafted polyvinyl acetals is also described in the previous German patent application P3835840.9.

In combination with a photopolymerizable mixture and a photoinitiator, the polymer obtained by the process is developed to form a transparent layer on the article. Depending on the particular composition, the layer is developed with an aqueous or aqueous alkaline solution of inorganic salts and/or surfactants. The layers are distinguished by a high degree of abrasion resistance, good ink receptivity, suitable shelf life and are therefore used in various applications, in particular in lithographic printing plates, screen printing stencils and photoresists.

Typically, the photopolymerizable mixture contains from 20 to 90, preferably from 35 to 75, weight percent polymer binder, based on the weight of the total non-solvent component of the mixture. 50% of the total amount of binder
The following, preferably up to 20% by weight, can be replaced by large amounts of conventional binders. Examples of suitable compounds are polyamides, polyvinyl esters, polyvinyl acetals,
Polyvinyl ether, epoxy resin, polyacrylic ester, polymethacrylic ester, polyester, alkyd resin, polyacrylamide, polyvinyl alcohol, polyethylene oxide, polydimethylacrylmide, polyvinylpyrrolidone, polyvinylmethylformamide, polyvinylmethylacetamide, and the list goes on. is a conjugate of monomers forming a homopolymer.

These binders are also advantageously water-insoluble, but are soluble or at least swellable in aqueous alkaline solutions. Examples of polymers of this type are malate resins, β-(methacryloyloxy)-ethyl N-)p-tolyl-sulfonyl)-carbamates, and copolymers of these and similar monomers with other monomers, as well as Vinyl acetate/crotonic acid copolymers, styrene/maleic anhydride copolymers, alkyl methacrylate/methacrylic acid copolymers, and methacrylic acid, higher alkyl methacrylate and methyl methacrylate and/or styrene copolymers, acrylonitrile and others.

The mixtures and materials according to the invention contain free radically polymerizable compounds having at least one terminal ethylenic type 2 bond. Preferably, esters of acrylic acid or methacrylic acid with mono- or polyhydric, preferably primary alcohols are used as the polymerizable compound. Preferably, the polymerizable compound should have one or more, especially 2 to 4 polymerizable groups. Examples of suitable polyhydric alcohols are ethylene glycol,
propylene glycol, butane-1,4-diol, butane-1,3-diol, diethylene glycol, triethylene glycol or polyethylene glycol or polypropylene glycol with a molecular weight of about 200 to 1,000, neopentyl glycol, glycerol,
Trimethylolethane, trimethylolpropane, pentaerythritol, bisphenol-A derivatives and reaction products of these compounds with ethylene oxide and/or propylene oxide. Bis-acrylates and bis-methacrylates containing urethane groups and prepared by reacting 1 mol of diisocyanate with 2 mol of hydroxyalkyl acrylate or hydroxyalkyl methacrylate are partially suitable. The diisocyanate may also be an oligomeric product obtained from the reaction of a diol with a molar excess of monomer diisocyanate. These and similar monomers containing urethane groups are DE-A2064079, DE-A-282219
0, DE-A-3048502 and DE-A-354
0480.

In addition to the esters mentioned above, amides of acrylic or methacrylic acid may also be used. Methylene-bis(meth)acrylamide and m-xylylenebis-(meth)acrylamide are examples.

The amount of monomer included in the mixture is usually about 10-80%, preferably 25-70% of the non-volatile components.
It is.

A large number of substances are used as photoinitiators.

Examples are benzoins, benzoin ethers, polynuclear quinones such as 2-ethyl-anthraquinone, acridine derivatives such as 9-phenylacridine or benzacrylidine, phenazine derivatives such as 9,10-dimethylbenz(a) phenazine, quinophsarin derivatives. or onorine derivatives, such as 2,3-bis-(4-methoxy-
phenyl)quinoxaline or 2-styrylquinoxaline, a quinazoline compound, or an acyl-phosphine oxyto compound. This kind of photoinitiator is DE-C202
7247, DE-C2039386, DE-A3728
168, EP-Bo, 011°786 and EP-Ao
, 220,5891 articles have been published. hydrazone,
Mercabt compounds, biryllium or thiopyrylium salts, xanthones, thioxanthones, benzoquinones, acetophenones, benzophenones, synergistic mixtures of ketones and hydroxyketones and dye rudoxy systems are also used. a photoinitiator with a photocleavable trihalomethyl group,
Particular preference is given to the corresponding compounds of the triazine or triazoline series. This type of compound is DE-A27182
59, DE A3333450 and DE-A3337024゜21
This is posted by myself. 2- (4-methoxystyryl)
-4,6-bis-trichloromethyl-S-triazine is a preferred example. These compounds are combined with photooxidative dyes, photoreducible compounds and
coinihlator) and e.g. EP-Ao, 2
84,939 and EP-Ao, 287,817.

The photoinitiator is typically between 0.1 and 0.1 with respect to the non-volatile components of the mixture.
15, preferably 0. It is used in an amount of 5-10% by weight.

Depending on their intended use and their required proportions, the photopolymerizable mixture may contain a large number of additives, for example inhibitors to prevent thermal polymerization of the monomers, hydrogen donors, dyes, colored or colorless. pigments, color formers, indicators, plasticizers and chain transfer agents.

The formation and amount of such additions depend on the field of application for which the photosensitive mixture is intended. In principle, care must be taken that the added substances do not absorb an excessive portion of the actinic radiation necessary for crosslinking. This is because this would result in a practical reduction in sensitivity to light.

The photopolymerizable mixture can also be combined with other negatively acting photosensitive compounds, in particular with diazonium salt polycondensation products. Suitable diazonium salt polycondensation products are condensable aromatic diazonium salts, such as diphenylamine-4
- condensation products of diazonium salts with aldehydes, preferably formaldehyde. Diazonium salt unit A-N2
In addition to including unit B;
It is also particularly advantageous to use cocondensates. These condensates are described in DE-A2024244. In general, DE-A27
The diazonium salt polycondensation products described in No. 39774 are preferred.

The diazonium salt unit A-N2X is preferably derived from the formula %. In the formula A certain R2 is a single bond or one of the following groups (CH2), -NR0-(CH2), -NR-8-(CH) ~NR'r-8-CHCo-NR'-0- R5-0-10-8-1 or -Co-NR' where q is a number of O to 5, " is a number of 215, R4 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, Carbon number 7
-12 aralkyl group or C6-12 aryl group, and R5 is a C6-12 arylene group.

A further preferred polycondensation product is the optionally substituted diphenylamine diazonium salt, which is first condensed with the aromatic compound R-0-CH2-B and then with the aromatic compound 1 1R-0-CH
Obtained by condensation with 2-B-CH2-0-R. Here, R1 represents a hydrogen atom, an alkali radical, or an aliphatic acyl radical, and B represents a radical of any one of the condensable compounds listed above. These condensable products are described in detail in EP-A 126,875.

The diazonium salt polycondensation product has a molecular weight of 0 to 40, preferably 0 to 30, with respect to the non-volatile constituents of the mixture.
contained in the mixture in an amount of

Furthermore, the polycondensable mixture can contain dyes and/or pigments which also serve to increase the contrast upon exposure and harden the layer. Suitable dyes are e.g. US-A3,21
8,167 and US-A 3.884,693.

Particularly suitable are, for example, Victoria Pur
e BlueFGA, Victoria Pure
Blue BO (C, 1, 42, 595), Ha I
ae old te Green, VIcLoria Blue
e B (C, 1, 44° 045), Renol Bl
ue B10-11 (C, 1, 74, 160), Cr
ystal Violet, rally Red 5
B (C, 1, 26, 125), Neozapon B
lue FLIE (C,1,5ohenL Blue
70), Br1lliant 131ue 5a
lt Acetate, Samarone N
avy-Blue, 0rasol Blue GN,
Zapon l'ast Fire-Red B(C
, 1,13,900:l) or Rhodalne G
GDN (C, I45.1GO). To increase image contrast after exposure, Mctanll Ye
low (C, 1, 13, 0G5), Methyl
Orange (C, 1,13,025) or phenylazodiphenylamine is used.

The support material is usually coated by flow coating, spraying or dipping from a suitable organic solvent or solvent mixture. The coating method depends on the required thickness of the layer,
The dry layer is usually 0. It has a thickness of 5 to 200 μm.

Suitable supports are, for example, magnesium, zinc, copper, mechanically, chemically, electrochemically granulated aluminum,
Anodized aluminum, steel, and polyester films, or cellulose acetate films, Perlongauge, etc., the surfaces of which have been pretreated. The support serves as a final support or temporary support material, from which the photosensitive layer is transferred by lamination to the product to be worked on.

For the S/F rating of the mixture according to the invention, it is necessary to keep the mixture away from the influence of atmospheric oxygen during photopolymerization, although it is not absolutely necessary to avoid contact with atmospheric oxygen during exposure. is usually preferred. When the mixture is used in the form of a thin copy layer, it is desirable to use a suitable protective film that is substantially oxygen impermeable. This film is self-retaining and can be peeled off prior to development of the copy layer. For this purpose, polyester films are suitable, for example. The protective film can also contain materials that can be dissolved in the developer solution or removed from at least the uncured areas during development. Suitable materials for this purpose are, for example, polyvinyl alcohol, vinyl alcohol/vinyl acetate copolymers, polyvinylpyrrolidone, vinylpyrrolidone/vinyl acetate copolymers, polyacrylic acid, butadiene/maleic acid Jl=! I
! Coalescence, polyvinyl methyl ether, polyphosphate,
such as sugar. Usually 0.1 to 10
, preferably has a thickness of 0.5 to 5 μm.

The recording materials produced using the photopolymerizable mixtures of the invention can be used on the one hand to form images on a suitable support or light-receiving sheet [7], and on the other hand to be used as printing plates, screens, resists, etc. It acts to create a relief.

Furthermore, it is also possible to use the photosensitive mixtures for the formulation of UV-curable printing inks or for the production of lacquers which can be cured by UV radiation and can be used for the protection of surfaces.

Preferably, the mixture is used in lithographic printing plates where aluminum is the preferred support material. Particular preference is given to pretreating the aluminum used for this purpose in customary methods, such as mechanical, chemical or electrochemical graining methods, optionally with anodization. Further treatment of this material with, for example, polyvinyl phosphonic acids, alkali metal silicates, phosphates, hexachlorozirconates, chromium hydrochloride, phosphates, polyacrylamides, and cellulose derivatives is advantageous.

The recording material obtained from the mixture is processed in the usual manner by exposing it imagewise and rinsing off the unexposed parts of the layer with a suitable developer.

The recording material is exposed below the original as is known in the art using a light source which emits light with the highest possible spectral part in the near ultraviolet region.

The material can also be exposed by laser radiation.

Suitable lasers for irradiation are short wavelength lasers of suitable performance, such as Ar lasers, krypton ion lasers, helium/cadmium lasers, with 300 to 600
For some layers that emit in the nm range,
CO2 laser emitting at about 10.6 μm or about 1,
It is a YAG laser that emits at 0.6 μm.

The developer is a neutral or preferably alkaline aqueous solution with a pH of 8 to 14, preferably 8.5 to 13, and a buffer salt, such as a water-soluble alkali metal phosphate, alkali metal silicate, alkali metal Borate salts, alkali metal carbonates, alkali metal acetates or alkali metal benzoates are used. Additional components used are wetting agents, preferably anionic wetting agents, preferably water-soluble polymers. The solution is a small amount, for example, 5 weight? It may also contain up to 6% by weight, preferably up to 2% by weight of a water-miscible white organic solvent. It is preferable to use a volatile solvent that does not easily evaporate, such as Ararifanuc alcohol, whose vapor pressure does not affect the handling of the developer in any way. Development is carried out in the usual manner by dipping, spraying, brushing or applying with a pad. If desired, the developed material can also be treated with a gum solution.

The photosensitive recording materials of the invention are distinguished by good reproducibility and a suitable shelf life. They are easily developed without skinning using developing solutions that are completely neutral in environmental concern.

The high printing volumes and excellent ink receptivity obtained with print formations made using the materials of the invention are particularly advantageous.

Printed stencils are also highly resistant to alkaline developers and other operating solutions. - To achieve high layer printing operations, the plate can be post-heated after exposure and/or the developed plate can be post-exposed.

The preparation of the polyvinyl acetal used in the examples is described below.

(a) Preparation of the polyurethane grafting strategy In each case, the diol component and the catalyst are first introduced into a reaction vessel equipped with the antibody, a nitrogen atmosphere is supplied, and the mixture is
Heated to reaction temperature of °C. The diisocyanate component was then weighed, taking care that the temperature of the reaction mixture did not exceed 120°C, preferably 100°C. After complete addition of the diisocyanate component, the mixture was post-heated to 80-100'C for up to 2 hours to complete the reaction. Completion of the conversion and thus termination of the reaction can be accomplished by known methods (
Determined by analysis of diisocyanate consumption using p, c, IR spectroscopy, suitable).

The detailed composition of the reaction mixture used in the examples and the calculated average molecule m (Mcal
c) is shown in Table 1 below. Molecule 2 is obtained from the molar ratio of diol component and diisocyanate assuming complete conversion of the NGO groups.

All of the products were made using isophorone diisocyanate as the diisocyanate component. In each case, 1,4-dimethylpiperazine was used as catalyst in an amount of 0.48 mol %, based on the diisocyanate.

(b) Preparation of the graft polymer In each case, the polyurethane graft skeleton was melted in a reaction vessel under a nitrogen atmosphere or dissolved in each case by adding a small amount of methanol and heated to a temperature of 60 to 100°C. The monomers to be grafted, optionally dissolved in a solvent (eg methanol) and containing a free radical initiator dissolved in the monomer, were slowly metered onto the polyurethane graft backbone in such a way that homopolymer formation was highly inhibited.

The maximum temperature of the reaction mixture is 120°C, more preferably 1
It is 00℃.

When the post-reaction was completed, the excess monomer residue was removed by azeotropic distillation. The composition of the individual reaction mixtures and reaction parameters are shown in Table 2 below.

All products were made using 0.2 mol% dibenzoyl peroxide (relative to the monomers used in each example). The intrinsic viscosity was determined in tetrahydrofuran at 25° C. using an Ostrild viscosity: 1 at a measurement concentration chosen such that no 11agenbach correlation was required. The amount by weight of monomer grafted is related to the weight of the total polymer.

(C) Saponification of Graft Polymer The graft polymer of Table 2 is transesterified at room temperature within 2 hours. For this purpose, the product was dissolved in methanol to give a 50% strength solution and mixed with methanol-soda lye (10% strength). Polymer hydrolysis products with various degrees of hydrolysis were obtained depending on the amount of alkali added and the degree of grafting of the graft polymer.

Grind the resulting gel using a regular mill. 1-1 particles with methanol (addition of acetic acid to neutralize the soda lye is preferred). X. Wash and dry. 1: The parameters and results are shown in Table 3 below.

(d) Preparation of polyvinyl acetal The graft polymer listed in Table 3 was dissolved in about 8 times the amount of distilled water. A corresponding amount of aldehyde and a small amount of 2,6-di-tert-butyl-4-methylphenol were added at room temperature. A solution containing a small amount of sodium octylsulfinate, 1/3 of the weight of the aldehyde in concentrated hydrochloric acid, and water was added dropwise to this solution while the antibody was being added. The mixture was stirred at room temperature for 1 hour, heated to 40° C. and continued stirring 1f for a further 2 hours. Then, use concentrated hydrochloric acid (
(same weight as aldehyde) was added and the antibody was continued at 40°C for an additional 2 hours. When the mixture was cooled to room temperature, the aqueous phase was decanted from the precipitated polymer and the polymer was dissolved in ethanol and poured into excess water to precipitate. The polymer was dried in a vacuum dryer at 40°C until constant weight.

In many cases where preferred embodiments of the invention are described in the Examples below, melons are given in parts by weight (pbw).

Unless otherwise specified, percentages and proportions are given in weight units.

Example 1 Polymer N 1.20 pbv Pentaerythritol triacrylate Technical grade mixture of pentaerythritol tetraacrylate 1.00 pbw2
-(p-)lichloromethylbenzoylmethylene)-3-ethylbenzothiazoline 0.15 pbw2
．． Blue azo dye obtained from 4-dinitroly6-chlorobenzenediazonium salt and 2-methoxy-5-acetylamino-N-cyano 0.03 pbw Dissolve the above and add methoxyethanol 50.001) l)
applying a coating solution containing SO to a 0.3+am thick aluminum foil electrochemically granulated in acetic acid;
Anodized in sulfuric acid, 0.1% of polyvinylphosphonic acid
Post-treated with a strong aqueous solution. ',, the dry layer weight of IK/GO was obtained.

The plate was then coated with polyvinyl alcohol (12 remaining acetyl groups).
It was coated with a 3.596 strength aqueous solution with a value of 4) at 96. After drying, a protective layer with a weight of 0.8 g/rd was obtained. The resulting printing plate was exposed using a 5KW halogen metal lamp at a distance of 110 cm between 40D and 13 stages of exposure wedges (vcdgc) with a density increment of 0.15.
'H, with a uniform optical density (density 1.5
7) and a uniform absorption over the effective spectral range was additionally placed as a neutral density filter. After exposure, the plate was developed with a brush pad in a developer of the following composition:

Sodium octyl silicate 5.0 pbv Sodium metasilicate x 5H20 1,0 pbv Distilled water 94.0 pbv The areas of the unexposed layer were completely removed within a few seconds.

Step 4 of the wedge stage was clear on the copy.

Even the thinnest elements of the original painting were recreated.

Example 2 Coating solution of Polymer M 1.000 pbw
Trimethylolethane triacrylate 1.500 pbv
-s-triazine 0.200 pbwC
crystal Violet (C, 1,42,555
) O, O 12 pbw 2-methoxyethanol dissolved in the above 50.000 pbv
To the layer support of Example 1: 1. Coating was carried out to give a dry layer weight of 5 g/rd.

A protective cover layer as described in Example 1 having a weight of 0.6 g/proof was applied. Exposure and development were performed as in Example 1 except that the exposure time was 18 seconds.

Example 3 A coating solution was prepared in the same manner as in Example 1 except that polymer N was replaced with polymer P having the same n. The solution was applied to the support material in such a way that a dry layer weight of <1.3 g/d, same as in the example, was applied to the cover layer. 8g:/C
It weighed -. Exposure and development were carried out in the same manner as in Example 1. Copies with excellent resolution and good ink receptivity were obtained.

Example 4 Polymer L 1.5ffOpbv
1 mole of 3-methoxy-diphenylamine-4-diazonium sulfate and 1 mole of 4,4'-bis-methoxy-methyl-diphenyldiazonium salt polycondensation product phosphonic acid (8596 strength) 0.910 pbw 0.049 pbw 2-(4-Methoxystyryl)-4,6-bis-trichloromethyl-S-triazine 0.1 G2 pbw Pentaerythritol Technical grade mixture of tri- and tetraacrylates Dye as described in Example 1 1.750 pbv O, 550 pbv Above A coating solution was prepared from butanone 70.000 pbv ethanol 4.000 pbw butyl acetate 2.000 pbw and applied to electrochemically granulated aluminum foil, followed by anodized L2 polyvinylphosphonic acid. The run was carried out in such a way that a dry layer weight of 2.1 g/proof was obtained.

The layer was exposed through the negative original for 25 seconds with a solid step 4 obtained with a test wedge.

Development was carried out with a developer having the following composition.

Sodium octyl sulfate 5.0 pbw Sodium metasilicate x 5 H201,5 pb Trisodium phosphate was accepted.

280,000 good prints were made.

Example 5 Coating solution was dissolved in Polymer O 2,50 pbw Mixture of technical agent 1 node 5.60 pbv Triazine specified in Example 4 0.20 pbv Azo dye specified in Example 1 0.30 pbv Above dissolved Butanone 25.00 pbw Ethanol 2.00 pbw Butyl acetate 1.00 After drying at 100°C, 35g of polyethylene terephthalate was prepared from pbw, stretched and oriented in two 25μm widths, and heat set;
Spin-coded to obtain a layer weight of /rd. The dry resist film prepared by this method was heated at 120°C with a phenoblast (ph
enoplast) laminated board coated metal plate (c la
d) was laminated using normal lamination tools. Exposure was carried out for 25 seconds using conventional exposure equipment. The original image used is 80μ
It was an original line drawing with a line width and space of less than m. Following exposure, the polyester film was carefully peeled off and the layer was developed in a spray development station for 90 seconds with the following developer.

Sodium octyl sulfate 5. Distilled water with Opbν above dissolved at 92.0 pbv After development, the plate was rinsed under running water for 30 seconds, etched for 30 seconds in an ammonium peroxide disulfate solution of about 1596, and then plated with the following plating solution. .

1, Messers, 5ehloeLter,
Geislingan/SLe1ge.

Copper bath 1' Glanzkapfer-Bad type (Bri I
Current density: 2,5 A/cd Metal stack (bnlld-up) Quantitative 12. 5μ
m2, nickel bath from the same manufacturer as above, Norma
30 minutes in type Current density: 4, OA/c metal lamination: 9.0μm
There was no evidence of cutting. Strip the coating at 50℃
It was carried out using a 5% strength KOH solution at a temperature of . The stripped copper was etched using a conventional etchant.

Example 6 Polymer Q 1.00 pbv
(C, 1, Barlc Blue 81)
A coating solution containing 50.00 pbv of propylene glycol monomethyl ether dissolving 0.02 pbv above was coated onto the aluminum support described in Example 4 to a dry layer weight of 1.3 g/M. The resulting printing plate was exposed through a test original and developed in the developer specified in Example 5.

When clamped into the sheet-fed offset press, the printed features immediately accepted the greasy printing ink.

Even after extended press stoppages, ink receptivity was excellent after printing 2 to 8 plates.

A good print of 95,000 was made and even the thinnest lines were reproduced.

Four of the plates made as described above were stored at 100<0>C in a drying oven for a period of 1 to 4 hours. After this heat treatment, the plates were imagewise exposed and developed with the developer specified above. In order to visualize any layer remnants (toning) remaining in non-image areas,
The dried plate was protected and colored with ink.

The plate kept in the oven for 1-2 hours was able to be developed on the sick foot.

Those versions did not show any substantial reduction in continuous tone step wedge. After 3 hours of storage, the continuous tone step wedge was reduced by one step. The inhibition to development was negligible.

There was little inhibition to development of plates stored for 4 hours.

The results showed that the mixture according to the invention had a relatively good resistance to hot storage.

Example 7 Polymer 8 A coating solution containing 70.000 pbv of propylene glycol monomethyl ether in which 2.280 pbv phenylazodiphenylamine (1,010 pbv triazine fl of Example 2, 211 pbv above) was dissolved in the support described in Example 1. The photosensitive layer was coated with a dry layer weight of 2.5 g/d using a 5 KW metal halide lamp.
Exposure was made through a standard negative original for 2 seconds. The photosensitive layer showed good discrimination between exposed and unexposed areas and was developed with the developer of Example 5 by means of a brush pad.

The unexposed layer areas were removed within 10 seconds of wetting with developer. The plate was then washed with water and dried.

Step 4 of the silver film continuous tone step wedge with optical density range 0.05-3.05 and density increments of 0.15 was well reproduced on the copy. Even the thinnest screen dots and lines of the original painting have been reproduced.

Polyvinyl alcohol layer (1296 residual acetyl groups,
Klj! 4) to the printing plate prepared as described above.
The coating was applied to give a dry layer weight of g/c. As a result of applying this oxygen barrier layer, the light speed of the photocured layer is 3.
096 increased. When the two printing plates were clamped in a sheet-fed offset press, the plate with the protective cover layer produced more prints than the plate without the cover layer. That is, printing operations have increased by about 250%.

Example 8 After exposure, the plates made in Example 7 (with and without oxygen barrier layer) were developed by heat treatment at 100° C. for 1 minute. In both cases, two additional distinct steps were obtained in the test wedge compared to the printing plate of Example 7, which was not thermally post-treated.

Post-heating also increased the number of printing runs. The increase was about 200% for the version without the cover layer and about 100% for the version with the cover layer.

The post-exposure step represents another possibility for increasing the number of prints in a comparable manner.

Claims (1)

[Claims] 1. As essential components: (a) a polymer binder having repeating vinyl acetal units; (b) having at least one terminal ethylenically unsaturated group;
a free radically polymerizable compound having a boiling point of more than 100° C. under normal pressure; and (c) a compound or a combination of compounds capable of initiating the polymerization of the compound (b) under the action of actinic light, and the binder comprises: A photopolymerizable compound characterized in that it is a graft polymer obtained from a polyurethane graft skeleton onto which chains containing vinyl alcohol units and vinyl acetal units are grafted. 2. The photopolymerizable mixture according to claim 1, wherein the chains to be grafted further contain vinyl ester units. 3. Photopolymerizable mixture according to claim 1, wherein the vinyl acetal units are derived from aliphatic or cycloaliphatic aldehydes. 4. Photopolymerizable mixture according to any one of claims 1 to 3, wherein the chains to be grafted further contain units of other ethylenically unsaturated monomers copolymerized with vinyl esters. 5. The photopolymerizable mixture according to claim 1, wherein the polyurethane is a polyadduct obtained from a diisocyanate and a diol. 6. According to claim 5, the diol is an aliphatic diol having 2 to 12 carbon atoms, a cycloaliphatic diol having 5 to 10 carbon atoms, or an aliphatic polydiol having a molecular weight of 200 to 10,000. Photopolymerizable mixture. 7. Polydiol containing 1 mole of diol and 0.1 to 0
．． 7. The photopolymerizable mixture of claim 6, which is a mixture comprising 7 moles of low molecular weight aliphatic diol. 8. The photopolymerizable mixture according to claim 5, wherein the diisocyanate is an aliphatic diisocyanate having 4 to 15 carbon atoms or a cycloaliphatic diisocyanate having 7 to 15 carbon atoms. 9. The photopolymerizable mixture of claim 1, wherein the polyurethane has a molecular weight of 200 to 100,000. 10. The photopolymerizable mixture according to claim 1, wherein the graft polymer has a number of hydroxyl groups in the range of 100 to 600. 11. Compounds that can be polymerized by free radical method are 1
is an acrylate or methacrylate of a hydrovalent or polyhydric alcohol, or an amide of acrylic or methacrylic acid;
A photopolymerizable mixture according to claim 1. 12, 20-95% by weight graft polymer, 5-70
2. The photopolymerizable mixture of claim 1, comprising % by weight of photopolymerizable compound and 0.1-15% by weight of photoinitiator. 13. The photopolymerizable mixture according to claim 1, further comprising a diazonium salt polycondensate. 14. Photopolymerizable recording material comprising a layer support and a photopolymerizable layer, said photopolymerizable layer comprising a mixture according to any one of claims 1 to 13.